The present invention relates generally to the field of driveline components, for example driveline components used in irrigation systems. In particular, the present invention relates to gearboxes and cartridge inserts for gearboxes that can be used in irrigation systems and other systems.
Worm wheel gearboxes have a worm gear that engages a bull gear. Such gearboxes are especially useful where low speed and high torque is desirable. Often, the worm gear is disposed on an input or drive shaft and the bull gear is linked to an output shaft. The gearbox can also be sealed. These worm wheel gearboxes are commonly used, for example, in agricultural irrigation systems and potato pilers.
Irrigation systems are widely used throughout the world to provide water for agricultural purposes in arid regions. Such systems include center pivot irrigation and lateral move systems. Typically, such systems include a series of spaced apart support towers connected by truss sections that support an elevated water distribution pipe between the towers. The trusses are linked together, enabling such irrigation systems to stretch to lengths of a thousand yards or more. In center pivot systems, the water distribution pipe extends radially from a central pivot communicating with a pressurized water supply. In lateral or linear move irrigation systems, the water distribution pipe extends laterally from a canal feed or hose drag system that provides a pressurized water supply.
Water passing through the distribution pipe is forced out through a number of sprinkler heads, spray guns, drop nozzles, and the like, spaced along the length of the pipe. Each tower in the system is supported on wheels that are driven at low speeds to move the tower in a circular path about the central pivot, or a linear path in the case of lateral move systems, to thereby irrigate a tract of land.
A number of drive assemblies have been developed for driving the support wheels of sprinkler irrigation systems. The most common drive assembly includes an electric motor connected to a center gear drive assembly, a first wheel gear assembly coupled to the center gear drive assembly by a first drive shaft, and a second wheel gear assembly coupled to the opposite side of the center gear drive assembly by a second drive shaft. Each of the first and second drive shafts typically has a driveline coupler at each end that allows the shafts to be quickly and easily pulled apart and put back together to facilitate field maintenance and/or towing from field to field.
The wheel gear assemblies generally include a wheel connected to a gearbox. The gearbox can be a sealed worm wheel gearbox that is provided having a worm disposed on a driveshaft. The worm engages a bull gear within the gearbox. The motor can drive a shaft which acts as the input shaft to the worm wheel gearbox. The bull gear is linked to an output shaft. The output shaft has an output flange which connects to the driven wheel. Rotation of the input shaft is thus transmitted via the gearbox to the output shaft, driving the wheels of the irrigation system.
A typical irrigation watering system has a number of such support wheels and each wheel or pair of wheels typically is driven by a motor and worm wheel gearbox as described. Worm wheel gearboxes are especially advantageous in this environment because once the drive motor stops, the worm and bull gear combination allow very little additional movement such as coasting. Thus, the irrigation system will remain in its position even if it is on a hill or other unlevel surface.
The farm environment tends to be wet, muddy, silty and dusty. Thus, these gearboxes are generally sealed to prevent contamination of the gearbox contents, such as the oil contained therein.
Worm wheel gearboxes are also commonly used in potato pilers. A potato piler comprises a conveyor disposed on a wheeled frame. To enable even piling of potatoes, the conveyor must be moved short, precise distances during operation. Potato pilers thus typically comprise a motor which rotatably drives a shaft and a worm wheel gearbox that transmits the shaft rotation to drive the wheels of the potato piler. This enables the potato piler to be moved short, precise distances when piling potatoes.